Crank counterbalance



Feb. 11, 1936. R. R. BLOSS 6 CRANK COUNTERBALANCE Filed Jan; 2, 1954 v 2 Sheets-Sheet 1 I N V EN TOR. [Pi chard 1? 5/055.

9 W A TTORNEYS.

Feb. 11, 1936. R BLOSS 2,030,046

CRANK COUNTERBALANCE Filed Jan. 2, 1934 2 Sheets-Sheet 2 IN V EN TOR.

. i 1Z9. 5 Pic/zaroR 3/055.

BY; v

ATTORNEYS} Patented Feb. 11,; 1936 PATENT OFFICE CRANK COUNTERBALANCE Richard R. Bloss, Columbus, Ohio, assignor to International-Stacey Corporation, Columbus, Ohio, a corporation of Ohio Application January 2, 1934, Serial No. 704,890

9 Claims.

My invention relates to crank counterbalances. It relates more specifically to crank counterbalances for use in connection with oil, gas or artesian wells. It has to do particularly with the provision of a crank counterbalance that may be used with the standard forms of cranks now commonly in use.

In the past, many types of crankv counterbalances have been devised. However, in many instances, these crank counterbalances have beenof such a nature as to require a specially-constructed crank. Also, in some instances, the means used for attaching the counterbalances to the crank arm has not been adequate to withstand the stresses and strains to which such a connecting means is subjected.

It is customary to provide the crank arm of well drilling or pumping mechanism with a plurality of openings adapted to receive a 'wrist pin by means of which the pitman of the mechanism may be attached thereto and at various locations therealong to vary the length of the pumping stroke, as is well understood by anyone familiar with the art. These cranks areusually provided in either one of two sizes,'namely, a shorter crank arm having four wrist-pin holes or a larger one having six wrist-pin holes. In many-cases, it is desirable to obtain a longer pumping stroke than it is possibleto obtain by use of the four-hole crank arm. Heretofore, if this were desired, it

. was necessary to replace the said four-hole crank arm by the longer type having six holes. If the wrist pin of the pitman is mounted in the outermost hole of the six-hole type of crank arm, a much longer stroke of the pumping mechanism is produced than when it is disposed in the outermost hole of the four-hole type. a

One of the objects'of my invention is to provide a crank counterbalance which may be readily applied to and detached from a crank arm'oi a standard type now commonly in use.

Another object of my invention is to provide a crank counterbalance which may be used with the standard types of crank arms now commonly in use, either the shorter or the longer type, but

which is particularly applicable for use with crank arms of the shorter four-hole type when it is desirable to obtain a greater pumping stroke than could be obtained by use of thefour-hole crank alone.

Another object of my invention is to provide a crank counterbalance which is-of such a type that it may be readily attached to or detached from a crank arm, and when attached to said crank arm, the means for attaching it thereto will be fully adequate to resist the stresses and strains to which such a connection is subjected. I In its preferred form, my invention contemplates the provision of a counterbalance weightv which is suspended in cooperative relation with the crank arm. The counterbalance weight structure embodies a main portion of suitable form which has means adjacent its upper portion adapted to firmly grip the lower end of the crank arm, in order that the crank arm and the 10 weight will be firmly attached together and will rotate together. The counterbalance weight also has a plurality ofremovable weights which may be mounted thereon to vary the counterbalance eiiect as desired. The counterbalance weight is 18 I adapted to serve in reality as an extension of the crank arm and means is provided for connecting the pitman of the pumping mechanism directly to the weight structure in order that a greaterpumping stroke may be obtained than is possible 20 when the pitman is connected to the crank arm at its outermost portion.

' The preferred embodiment of my invention is shown in the accompanying drawings wherein similar characters of reference designate corre- 25 sponding parts and wherein:

Figure 1 is a view oi'well pumping or drilling mechanism having a counterbalance made in accordance with my invention associated with the crank arm thereof,- the crank arm being of the 30 shorter four-hole type.

Figure 2 is a side elevation of a crank counterbalance structure made in accordance with my invention and showing how it is applied to the crank arm. I

Figure 3- is a vertical section taken substantially on line 3-3 of Figure 2.

Figure 4 is a perspective view of a portion of the crank'counterbalance and a portion of the lower end of the,crank arm, illustrating in detail 0 the means for embracing the lower end of the.

crank arm.

Figure 5 is a detail, in section, showing a part of the upper portion of the counterbalance weight and how the lugs adapted to grip the lower end of the crank arm fit into the edge of the counterbalance weight. I

With reference to the drawings, I have shown in Figure 1 well drilling or pumping mechanism embodying a. derrick I having a Samson post 2 One end 01' the walking'beam 3 is, connected to a polished rod 5 which isconnected to a sucker rod operating in the casing of the well. The opposite end of the walking beam 3 is connected to a pitman 6 in the usual manner. This pitman may be connected to'the crank arm I of the pumping mechanism or a counterbalance weight 8, as will be described more fully hereinafter.

From reference to Figure 3, it will be seen that the crank arm I is supported on the outer end of a crank shaft 9. The outer end of this crank shaft is rotatably mounted in a bearing disposed on the upper end of a jack post I. The crank arm 1 is of a standard type but, as will be explained more fully hereinafter, this crank arm is of the shorter four-hole type.

The counterbalance weight I which is associated with the crank arm is more clearly illustrated in Figure 2. This counterbalance weight embodies a body portion II which is suspended in cooperative relation with the lower end of the crank arm I.

The means for suspending the counterbalance unit in cooperative relation with the crank arm. embodies a pair of rods l2 having their lower ends extending through slots l3 formed in the body portion H of the counterbalance weight at each end thereof. 'These slots have their outer sides open so that the entire rod may be slipped laterally outwardly therefrom. The rods l2 have.

heads IS'formed on their lower ends. Cut-out portions I4 are provided in each end of the body portion ll andare adapted to permit slipping of rods i2 into the" innermost portions of slots If, it being understood that inward movement of the heads l5 will be permitted. 0n the rods l2 directly above heads l5, washers I! are disposed.

Each of these washers I5 is provided with a concave upper surface adapted to cooperate with a convex surface lia against which the washers will bear. Due to this concave surface on the 'washer and the convex surface on the shoulder,

outwardly as at l3 and then downwardly andinwardly as at l3a, in order to permit this adjustment of rods l2. Y

The rods l2 extend upwardly and inwardly and pass through slots II which are provided in the cap structure I'I. Theseslots I are similar to slots l3 and have open outer sides so that the rods may be swung laterally and outwardly therefrom. The cap structure ll has a socket it formed in its under surface so that. it can fit over the upper end of the crank arm I and will be maintained in position thereon. When the counterbalance unit is in operative position as shown in Figure 2, the rods l2 extend a considerable distance up past the upper ends of slots ii. The upper ends of the rods l2 have nuts, l9 threaded thereon and directly below these nuts washers II are disposed. Each of-these washers has a concave lower surface resting on a convex shoulder "a. These cooper-. sting concave and convex surfaces are provided for the same reasons as those at the lower endssame purpose that the inner sides of slots l3 are similarly inclined. It will be apparent that by adjusting the nut IS, the counterbalance weight may be bodily raised or lowered as desired. The upper ends of rods 12, in Figure 2, are shown as being cut ofi but it will be understood that they are of such length as to permit lowering of the counterbalance weight on a support where the weight will occupy a position in non-interfering relation with the lower end of the crank arm.

In order to firmly attach the counterbalance weight structure to. the crank arm 1, I provide the following structure. The upper edge of the body portion of the counterbalance weight is provided with a groove formed therein, as illustrated at 20 in Figures 2, 3 and 5. This groove is of substantially less width than the thickness of the body portion II and has beveled sides. When the crank counterbalance is adjusted into operative position as shown in Figures 2 and 3, the extreme lower end of the crank arm will project slightly into this groove as illustrated at 2|, and the beveled edge of. the crank will wedge between the beveled sides of groove 20. Disposed at each side of the lower end of the crank arm, is an adjustable lug member 22. These lug membersare provided with downwardly projecting tongues 20* which fit into groove 20 and which operate therein. The tongues 20' projecting into groove 20 preclude lateralw displacement of lugs 22 and consequently prevent back and forth wobbling of the ent e counterbalance as will be later seen. These 1 members 22 are provided with outer surfaces 23 adapted to fit around the beveled side edges of the crank arm I. These outer surfaces 23 are shaped to correspond to the contour of the side edges'of the lower portion of the crank arm 1 and are provided with grooves adapted to receive said edges, as will be apparent from the drawings. The lug members 22 are movable laterally with relation to the crank arm. The tongues 20' will operate in the groove 20 and the lower surfaces of the laterally projectingportions 22' of the lugs will slide back and forth on the surfaces 22a at each side of groove 20. It will be apparent that the central portion of the body portion II is cut out midway of its ends to receive the lugs 22 and other parts of the attaching means to be described. An upstanding wall member 22?) is provided behind the lugs 22 but in order to facilitate removal of the lug members such a wall member is not provided in front thereof. Thus, the lug members 22 may be adjusted laterally as described.

In order to force the lugs firmly in contact with the sides of the crank arm, I provide wedge members 24 which are disposed outside of thelug members 22. The outer surface of each of the lug members 22 is inclined downwardly and outwardly as indicated at 25. The inner surface of each of the wedge members 24 is correspondingly beveled and its outer surface is straight as indicated at 26 and is adapted to abut a straight vertical wall 26' on the body portion ll. Tongue and groove connections 3| are provided to preclude relative lateral displacement between lugs 22 and wedge members 24. Bolt members 21 pass upwardly through openings formed in the body portion ll of the counterbalanced weight and in the'wedges 24. These bolts have nuts threaded-on their upper ends. The heads 28 of the bolts are disposed in chambers 29 formed in the body portion of the counterbalance weight which will cooperate withthe heads 28 to prevent bodily rotation of the bolts. These chambers 29 are of such a height as to permit dropping down of bolts 21 a considerable distance after the nuts are removed from the upper ends thereof and thereby facilitate removal of the wedge members. Thus, the wedge members 24 and the lug members 22 may be entirely removed when desired, andsince a wall similar to wall 22b is not disposed in part thereof, removal of the wedge members and lugs is facilitated. 'Due,to the fact that the wedge members and lugs are entirely removable, when it is desired to dispense with use of the counterweight, it may be dropped and need only be dropped slightlyin order to dispose it out of interfering relation with the end of the crank arm 1. Also, since the bolts 21 can be dropped, there will be no danger of the upper ends thereof interfering with rotation of the crank arm 1.

It will be apparent that when using this attaching means, the cap member I8 is first disposed on the upper end of the crank arm as illustrated in Figure 2, it being understood that the arm will occupy the position indicated. The nuts 19 on the upper ends of the rods l2 will then be adjusted to cause the counterbalance weight to be raised into a position shown in Figure 2 with the lower end of the crank arm extending slightly into the slot20 and wedged therein. The lugs 22 are then disposed on each side of the lower end of the crank arm and the wedges 24 are properly positioned. It will be apparent that by screwing down the nuts on the upper ends of bolts'2l, the wedge members will be forced downwardly and will wedge between the lugs 22 and the outer ends of slot 20. Consequently, the lugs 22 will be caused to firmly grip the lower end of the crank arm I. A substantial space 30 willalways remain between the lower end of each of the wedge members and the bottom of slot 20, as shown in Figure 2. Thus, the nuts on the bolts 21 may be adjusted from time to time to maintain the lug members 22 in firm contact with they crank arm.

It will be apparent'that the lugs 22 gripping the sides of the crank arm 1, will exert their force against such crank in a horizontal direction. Also, the rods 12 pulling up on the weight 8 will cause wedging of the lower end of the crank arm in the groove 20 and will aid in keeping the lower end of the crank arm seated between lugs 22. In other words, both a horizontal and a vertical wedging action are produced.

The body portion of the counterbalance weight is provided with sets of weights l2 and 33 which are suspended therefrom by means of bolts 34. The bolts 34 have heads 35 formed on their lower ends which fit into sockets formed in'the lowermost weight 36 in such a manner that the heads cannot turn. These bolts extend upwardly into openings 31 formed in the bodyportion of the counterbalanceunit. Fassages 38 (Figure extend laterally from the openings 21 adjacent their upper ends in order to permit access to' nut members 39 threaded on the upper ends of bolts 34.

A plurality of weight members 40 may be disposed between the lowermost weight member 36- andthe body portion II., The adjacent weights are provided with bosses 40' which fit into sockets in the other of the weights in order to aid in precluding relative lateral displacement of the weights. These weight members are provided with U -shaped slots (not shown) which will flt around the bolts 34.

. six-hole crank arm of Thus, the intermediate weights 4| may be removed or replaced as desired without completely removing the bolts 34 or disturbing the lowermost weights 26. .When the desired weights are in position the nuts 39 may be screwed down on the bolts 34 to tightly clamp 5 all of the weights in position. In Figure 5 it will be seenthat opening 31 extends upwardly a considerable distance. Thus, it some of the weights 40 are removed, the nut 39 may be adjusted to cause bolt 31 to move upwardly a sufllcient distance until all the weights are tightly clamped together.

As previously stated, the crank arms are usually provided with a plurality of openings spaced therealong in order that the pitman may be at- I ity of spaced openings 4| adapted to receive the wrist pin which is used for connecting the pitman thereto.

It is well known to a person familiar with this art that sometimes it is desirable to obtain a longer pumping stroke than could possibly be obtained by use of a four-hole crank arm of the type illustrated in the drawings. Previously, if this was the case, it was necessary to replace the four-hole type of crank arm by a six-hole type, which is considerably longer. However, I have provided a counterbalance weight which makes this unnecessary and which can be used with the shorterfour-hole t and by which it will be possible to obtain a onger pumping stroke than is possible with the shorter crank arm alone.

It will be apparent from an examination of the drawings that when the counterbalance unit when it is desired to obtain a maximum pumping stroke. This opening 4| is so formed that when the counterbalance unit is in operative position it will be approximately in alignment with the openings'4i-in the crank arm 1. Thus, when desired, the wrist pinmay be disposed in this opening and, consequently, the pitman 6 will be connected directly to the weight structure 8. Of course, if desired, morethan one opening could be formed in the body portion of the weight structure. This renders unnecessary the replacement of the short four-hole crank arm 1 by a greater length in order to gate. maximum pumping stroke of adequate length. ,The length of the crank arm is increased by the distance "A" illustrated by the arrows in Figures 3 and. It will be apparent from the above description that I have provided a counterbalance unit having many desirable features. This counterbalance unit may be readily applied to crank arms of the-standard types and may be readily detached therefrom. The attaching means is .of such a type that'it will adequately resist all stresses and strains to which it might be subjected. Due. to the fact that the counterbalance weight serves as an extension of the crank arm and has a means for connecting the pitman di rectly thereto, a. maximum pumping stroke of greater length may be obtained. Thus, it will be possible. by using this counterbalance unit with crank arms of the'shorter four-hole type to secure a maximum pumping stroke of much greater length than could be obtained by use of the fourhole type of crank arm alone.

Oi course I have used the terms tour-hole of said crank arm for gripping the lower end of pumping mechanism, a counterbalance weight, means for suspending said counterbalance weight in cooperative relation with said crank arm, said means including a cap member, a plucooperative relation with said crank arm, a plu- 5 type and "six-hole type of crank arms for rality of rods having one end connected to the 5 illustrative purposes only and I do not intend to cap member and the other end connected to said be limited thereby. counterbalance weight, said rods being adjust- Having thus described my invention, what I able to cause movement oi. the weight radially of claim is:' said crank arm, said weight having a recessed 0 1. In combination with the crank arm of a portion in its upper edge, a slot formed in the well pumping mechanism, means for suspendbottom oi said recess, the lower end or said crank ing a counterbalance weight structure in 00- arm fitting into said slot when the rods are propoperativ'e relation with said crank arm, said erly adjusted, a lug disposed in said slot at each means including a cap member, a plurality of side of said crank arm for gripping the lower end rods havingone of their ends connected to said of said crank arm, means for causing said lugs 15 cap member and their opposite ends attached to to firmly grip said crank arm comprising a pair said weight structure, a pair of lugs disposed on of wedge members each of which is disposedbethe'upper portion 01' said weight structure and tween one 01' said lugs and the corresponding end adjustable laterally thereof into gripping relaof. said recess, and adjustable means for causing tion with the lower portion of said crank arm, said wedge members to be tightly wedged in pogo and a pair of wedge members mounted on' the sition and to cause said lug members to grip said upper portion or said weight structure and adaptcrank arm. ed to maintain said lugs in gripping relation 5. In combination withthe crankarm of a well with said crank arm. pumping mechanism, a counterbalance weight,

2. In combination with the crank arm 01' a means for suspending said counterbalance weight 25 well pumping mechanism, a counterbalance in cooperative relation with said crank arm, said weight, means for suspending said counterbalmeans includinga member from which the weight ance weight in cooperative relation with said is suspended, a plurality of rods having one end crank arm, said means including a cap member connected to said member and the other end conwhich fits over the upper end of said crank arm, nected to said counterbalance weight, said rods 30 a plurality of rods having one of their ends conbeing adjustable to cause movement of the weight nected to the cap member and their opposite radially or said crankarm, a slot formed in the ends connected to said counterbalance weight, upper edge of said weight, the lower end of said the one end of each ofsaid rods fitting into an crank arm fitting into said slot when the rods open-ended slot in said cap member and the opare properly adjusted, a lug disposed in said 5 posite end of each 01' said rods fitting into an slot at each side of said crank arm for gripping open-ended slot in said counterbalance weight, the lower end of said crank arm, and means said'rods being adjustable to cause movement 01' for causing said lugs to firmly grip said crank the weight radially of said crank arm, said weight am, Said means 0011191181118 8 P Of adjustable 40 having a recessed portion in its upper edge, a. wedge members. 40

slot formed in the bottom of said recess, th 6. An attachment for the crank arm of well lower end of said crank arm fitting into said. pump ng wmpl'lsing counterbalslot when the rods are properly adjusted, a lug ance weight structure adapted to be disposed in disposed in said slot at each side oi. said crank cooperative relation with said crank arm, said arm for gripping the lower end or said crank arm, weight structure having a recess formed in its 45 means for causing said lugs to ifirmly grip said pp ed a 8101; formed in the bottom of said crank arm comprising a pair of 'wedge members recess, a pair of, lugs'disposed in said recesaand each of which is disposed between one of said adjustable therealong,'said lugs being adapted lugs and the corresponding end. of said recess, to grip the lower end or said crank arm, means and adjustable means for causing said wedge I for maintaining said lugs in gripping relation to 50 members to be tightly wedged in position and the crank arm, said means comprising wedge to cause said lug members to grip said crank arm. members each or which fits between one 01' said 3. In combination with the crank arm or a lug members and the corresponding end of said well pumping mechanism, a counterbalance recess.

weight, means for suspending said counterbal- '7. An attachment for the crank arm or a. well- 55 ance weightin cooperative relation with said pumping mechanism comprising a counterbalcrank arm, said means including a. cap member ance weight structure adapted to be disposed in which fits over the upper end of said crank arm. cooperative relation with said crank arm, said a pl l y f rods having one end connected to weight structure having a recess formed in its 0 the cap member and the other and connected to upper edge a, p anof lugs disposed in said re s said counterbalance weight, the one end 01' said' and adjustable thereglong; am lugs being trods fitting into an open-ended slot in said cap ed to grip thelgwer end of said crank arm means member and the opposite end of each of said for maintaining said lugs 1 gripping relation to rods fitting into an open ended slot insaid counth crank arm, said means comprising wedge ter alanc w i ht, s d ods e nsadj ta members each of which fits between one or said 65 cause movement of the weight radially of said lug b r and the corresponding end of said crank arm, a slot formed in the upper edge of i said weight the end said (Wank arm 8. An attachment for the crank arm or wellfitting in) said slot when thfi rods are properly. pumping comprising a gounterbaladjusted, a lug disposed in said'slot ateach side m m mum-Mfg be 11 m i 70 said crank arm, and means for causing said lugs to firmly grip said crank arm, said means comprising a pair of adjustable wedge members.

4. In combination with the crank arin of a well rality oi lugs disposed on said wei ht structure andbeing slidablebodily andlaterallyalong said' Welsh? structure into and out of grippi g relation withtbecrankammeansiormaintainingsaid 75 e lugs in gripping relation to the crank am, said means comprising wedge members each of which fits between one of said lug members and an abutmeans including a member from which the weight is suspended, a plurality of rods having one end connected to said member and the other end connected to said counterbalance weight, said rods being adjustable to cause movement of the weight radially of said crank arm, one end of each of said rods fitting into an open-sided slot in said member and the opposite end of each of said rods fitting into an open-sided slot in said counterbalance weight, said member having a convex portion formed thereon adjacent the upper end of each slot formed therein and said weight having a convex portion formed thereon adjacent the lower end of each slot formed therein, each of said rods being provided with a member adjacent each end having a concave portion for cooperating with one of said convex portions.

' RICHARD R. BLOSS. 

